Though many historical accounts of Nero describe him as weak and frail, one may know merely by looking at a bust that he had a noble face from which blue eyes burned fiercely.
I found a forum post asking the same question. One of the answer refers to verism, which is an artistic movement advocating realism, hence producing accurate representation of historical figures. However, it is a movement that was happening only in the Roman Empire, and not consistently during its reign.
How can historian assess the accuracy of busts and statues of ancient history? Has there been research about this?